He had to show up at work because he was never formally fired. If he hadn't showed up at work but still collect his paychecks then it would have been breaking the law and the company would have clawed back all paychecks. By showing up at work he was just fulfilling his contractual obligations, it wasn't his fault nobody gave him any work to do so he was legally entitled to collect paychecks while playing games and doing side projects at work.

> There are many people around me who seemingly do nothing, he would just blend into the crowd.

Not always the case. It might be a thing in large enterprises of US/Anglophone countries from what I noticed, but in German speaking countries it's not really common for people to show up at the office and do nothing all day, the efficiency and work ethic tends to be relatively higher, especially at smaller offices. So you stand out, people will gossip and eventually someone above will inquire about that guy without a team doing nothing.

Sure, you can lie to everyone around you about why you're still here without your team doing nothing so they stop asking questions, but lying can still be considered a felony here if the thing ends up in court and get you in actual legal trouble later as they will still find out eventually about you, so it's best to be honest and legally enjoy the ride while it lasts.